title: Physiological and molecular responses of springtails exposed to phenanthrene and drought.
abstract: Interaction between effects of hazardous chemicals in the environment and adverse climatic conditions is a problem that receives increased attention in the light of climate change. We studied interactive effects of phenanthrene and drought using a test system in which springtails (Folsomia candida Willem) were concurrently exposed to a sublethal phenanthrene level via passive dosing from silicone (chemical activity of 0.010), and sublethal drought from aqueous NaCl solutions (water activity of 0.988). Previous studies have shown that the combined effects of high levels of phenanthrene and drought, respectively, interact synergistically when using lethality as an end-point. Here, we hypothesized that phenanthrene interferes with physiological mechanisms involved in drought tolerance, and that drought influences detoxification of phenanthrene. However, this hypothesis was not supported by data since phenanthrene had no effect on drought-protective accumulation of myo-inositol, and normal water conserving mechanisms of F. candida were functioning despite the near-lethal concentrations of the toxicant. Further, detoxifying induction of cytochrome P450 and glutathione-S-transferase was not impeded by drought. Both phenanthrene and drought induced transcription of heat shock protein (hsp70) and the combined effect of the two stressors on hsp70 transcription was additive, suggesting that the cellular stress and lethality imposed by these levels of phenanthrene and drought were also additive.
authors.affiliation: Department of Bioscience, Aarhus University, Vejlsøvej 25, PO Box 314, DK-8600 Silkeborg, Denmark. Electronic address: martin.holmstrup@dmu.dk.
authors.forename: Martin
authors.initials: M
authors.lastname: Holmstrup
authors.forename: Stine
authors.initials: S
authors.lastname: Slotsbo
authors.forename: Stine N
authors.initials: SN
authors.lastname: Schmidt
authors.forename: Philipp
authors.initials: P
authors.lastname: Mayer
authors.forename: Christian
authors.initials: C
authors.lastname: Damgaard
authors.forename: Jesper G
authors.initials: JG
authors.lastname: Sørensen
mesh_terms: D000818:Animals; D001181:Arthropods / Q000187:drug effects / Q000502:physiology*; D055864:Droughts; D051549:Glutathione S-Transferase pi / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D010616:Phenanthrenes / Q000633:toxicity*; D012989:Soil Pollutants / Q000633:toxicity*; D013312:Stress, Physiological
chemical_list: D018840:HSP70 Heat-Shock Proteins; D010616:Phenanthrenes; D012989:Soil Pollutants; C031181:phenanthrene; D051549:Glutathione S-Transferase pi; C496558:Gstp1 protein, rat
keywords: Climate change; Collembola; Desiccation tolerance; Passive dosing; Polycyclic aromatic hydrocarbons